The 3rd Generation Partnership Project (3GPP) is responsible for the standardization of the Universal Mobile Telecommunication System (UMTS) and Long Term Evolution (LTE). The 3GPP work on LTE is also referred to as Evolved Universal Terrestrial Access Network (E-UTRAN). LTE is a technology for realizing high-speed packet-based communication that can reach high data rates both in the downlink and in the uplink, and is thought of as a next generation mobile communication system relative to UMTS. In order to support high data rates, LTE allows for a system bandwidth of 20 MHz, or up to 100 Hz when carrier aggregation is employed.
In a multi-carrier or carrier aggregation system, each carrier is generally called a component carrier (CC). A component carrier is sometimes also referred to as a cell. The term “component carrier” (CC) refers to an individual carrier in a multi-carrier system. Carrier aggregation (CA) is also referred to as “multi-carrier system”, “multi-cell operation”, “multi-carrier operation”, or “multi-carrier” transmission and/or reception. This means that CA is used for transmission of signaling and data in the uplink and downlink directions. One of the CCs is the primary carrier or anchor carrier and the remaining ones are called secondary or supplementary carriers. Generally, the primary or anchor CC carries the essential UE specific signaling. The primary CC exists in both the uplink and downlink directions. The network may assign different primary carriers to different user equipments (UEs) operating in the same sector or cell. In carrier aggregation, the UE may have more than one serving cell: one primary serving cell and one or more secondary serving cell. The serving cell may interchangeably be called the primary cell (PCell) or primary serving cell (PSC). Similarly, the secondary serving cell is interchangeably called the secondary cell (SCell) or secondary serving cell (SSC). Regardless of the terminology, the PCell and SCell(s) enable the UE to receive and transmit data. More specifically, the PCell and SCell exist in DL and UL for the reception and transmission of data by the UE. The remaining non-serving cells are called neighbor cells.
The CCs in CA may or may not be co-located in the same site or base station. For instance the CCs may originate (i.e. be transmitted/received) at different locations, e.g. from non-colocated base stations, or from a BS and remote radio heads (RRH) or remote radio units (RRU). Some well known examples of combined CA and multi-point communication are DAS, RRH, RRU, CoMP, multi-point transmission/reception etc. The embodiments disclosed herein also apply to the multi-point carrier aggregation systems.
A minimization of drive test (MDT) feature has been introduced in LTE and HSPA release 10. The MDT feature provides means for reducing the effort for operators when gathering information for the purpose of network planning and optimization. The MDT feature requires that the UEs log or obtain various types of measurements, events and coverage related information. The logged or collected measurements or relevant information are then sent to the network. The UE can collect the measurements during connected as well as in low activity states e.g. idle state in UTRA/E-UTRA, cell PCH states in UTRA etc. The UE can also be configured to report the CGI of the target cells along with other measurements (e.g. RSRP, RSRQ, CPICH measurements, radio link failure report, BCH failure rate, paging channel failure rate etc).
Several positioning methods exist for determining the location of the target device, which can be a UE, mobile relay, PDA etc. Some well known methods are:                Satellite based methods; these use A-GNSS (e.g. A-GPS) measurements for determining UE position        Observed time difference of arrival (OTDOA): Uses UE RSTD measurements for determining UE position in LTE        Uplink time difference of arrival (UTDOA): Uses measurements done at LMU for determining UE position        Enhanced cell ID: Uses one or more of UE Rx-Tx time difference, BS Rx-Tx time difference, LTE RSRP/RSRQ, HSPA CPICH measurements, angle of arrival (AoA) etc for determining UE position.        Hybrid methods: Using measurements from more than one method for determining UE position.        
In LTE, the positioning node (aka E-SMLC or location server) configures the UE, eNode B or LMU to perform one or more positioning measurements. The positioning measurements are used by the UE or positioning node to determine the UE location. The positioning node communicates with UE and eNode B in LTE using LPP and LPPa protocols.
Performance requirements are specified in order to ensure that a wireless device properly implements a particular feature. For instance, to guarantee that a user equipment (UE) supporting the Multiple Input-Multiple Output (MIMO) feature exhibits good performance in practice, the corresponding MIMO performance requirements are specified. The performance requirement is also verified by the virtue of conformance tests.
Performance requirements can be broadly divided into the following two main categories:                Conducted performance requirements        Radiated performance requirements        
It is important to note that the term “performance requirement” as used in this disclosure is a generic term. In the literature, different terminologies are used to denote performance requirements specified for different types or aspects of features. For instance, some well known terms are core requirements, radio resource management (RRM) requirements, and demodulation requirements. These terms will also become apparent with specific examples. Nonetheless, the term “performance requirement” hereinafter covers any type of requirement without limiting it to the above mentioned examples.
Conducted performance requirements or, more briefly, “conducted requirements”, are to be met by the wireless device at a well defined point or location on the wireless device. Such a point is commonly called as test point or test port or test location where the requirements should be met. Typically the conducted requirements are to be fulfilled at the antenna connector of the wireless device, i.e. the test point or location is the antenna connector. The test point may also be located e.g. between the baseband and radio part of the wireless device.
In order to verify the conducted requirements, tests are done by setting up a test system in a lab or in any controlled environment. In a test system the test point, e.g. antenna reference point or antenna connector, of the wireless device under test (DUT) is connected to the test equipment (TE) via a coaxial cable, i.e. a non-wireless connection. The TE is also commonly called system simulator (SS). The channel model, radio environment or other conditions required in the tests are realized by additional devices in the test system e.g. fader, signal generator, signal attenuator, signal amplifier etc.
Conducted performance requirements can be classified into the following three main groups:                Radio requirements        Baseband requirements        Radio resource management (RRM) requirements        
Radio requirements are further classified into:                RF receiver requirements e.g. receiver sensitivity        RF transmitter requirements e.g. transmit power accuracy        
Typically, baseband requirements refer to the performance obtained after demodulating the received signal. Baseband performance may for example be expressed in terms of the demodulation performance, which in turn may be expressed in terms of achievable throughput, e.g. usable bit rate, block error rate (BLER) etc.
Radio resource management (RRM) requirements are typically specified to guarantee mobility performance of the wireless device. Examples of the RRM requirements are handover delay, measurement reporting delay, accuracy of measurement quantity etc.
The conducted requirements are typically extensively specified. Indeed, the performance of features is primarily expressed and verified using the conducted requirements for UE, BS and other wireless devices. The conducted radio and baseband requirements for UTRA UE and UTRA BS are specified in 3GPP TS 25.101, version 10.3.0 and TS 25.104, version 10.3.0, respectively. The radio and baseband requirements for E-UTRA UE and E-UTRA BS are specified in 3GPP TS 36.101, version 10.4.0 and 3GPP TS 36.104, version 10.4.0, respectively. The RRM requirements for UTRA and E-UTRA are specified in TS 25.133, version 10.3.0 and TS 36.133, version 10.4.0, respectively.
The radiated performance requirements are to be met by the wireless device in the air. They are interchangeably called over the air (OTA) performance requirements. The radiated performance is typically worse than the corresponding conducted requirements since the latter do not take into account all factors contributing to signal loss or dispersion in the air. The OTA performance is heavily dependent on the antenna integration. Design parameters such as radiation pattern, total radiated antenna efficiency, correlation and gain imbalance will impact the OTA performance. The radio performance thus also depicts true or at least more realistic performance achieved by a wireless device in the field.
Some well known examples of performance metrics which are used for verifying the radiated performance are Total Radiated Power (TRP), Total Radiated Sensitivity (TRS), Mean Effective Radiated Power (MERP), Sensitivity (MERS) etc. These metrics are defined in 3GPP TS 25.144, version 10.0.0, and 25.914, version 10.2.0. The TRS and TRP are the radiated counterparts of the conducted receiver sensitivity and maximum output power respectively. Another example of an OTA requirement is the Specific Absorption Rate (SAR), which is used to measure impact on the human body from the exposure of RF EMF transmitted by the UE. SAR is a measure of the maximum energy absorbed by a unit of mass of exposed tissue of a person using a mobile phone, over a given time or more simply the power absorbed per unit mass. For certain use-cases where the UE is close to a human body, the SAR requirement stated by regulatory organization such as FCC will limit the maximum output power of the UE. There are UE types that can be used in several positions relative to the body, e.g. for speech and surfing, with different SAR requirements enabling the possibility to adapt the output power to optimize TRP performance and still fulfil FCC requirements.
A key challenge is to correctly define and verify the radiated performance requirements. For instance, to avoid environmental perturbations the measurements must be performed in a shielded enclosure to prevent unwanted environmental signals or reflections. Hence typically the OTA performance is verified by setting up the test in a suitable chamber, e.g. in a reverberation chamber or an anechoic chamber. This is described in more detail in 3GPP TS 25.914, version 10.2.0.
It is quite likely that two or more similar types of wireless devices (e.g. mobile terminal) have substantially different radiated performance. However their conducted performance is the same. Even different types of wireless devices, such as a plugged in device and a mobile terminal, may have the same conducted performance, but their radiated performance may still differ significantly. Furthermore, the radiated performance may also change due to various different factors, e.g. varying environmental conditions. In existing technologies, the conducted performance is typically used for radio network operation such as scheduling, power control etc. This may lead to substantial mismatch between the expected performance and the real performance in the network. As a consequence, the actual performance of the wireless devices in the field is deteriorated and the expected target performance is not met. In some cases resources are also wasted, since resources cannot be efficiently utilized.